– within 5,000 feet of a public use heliport which exceeds a
25:1 surface.
approach area, which would result in the vertical distance
between any point on the object and an established minimum
instrument flight altitude within that area or segment to be less
than the required obstacle clearance.
Any highway, railroad, or other traverse way whose prescribed
adjusted height would exceed the above noted standards.
(4) A height within an enroute obstacle clearance area, including
turn and termination areas, of a Federal Airway or approved
off‐airway route, that would increase the minimum obstacle
clearance altitude.
When requested by the FAA:
– Any construction or alteration located on a public use airport or
heliport regardless of height or location.
(5) The surface of a takeoff and landing area of an airport or any
imaginary surface established under § 77.19, 77.21, or 77.23.
However, no part of the takeoff or landing area itself will be
considered an obstruction.
(CFR) Title 14 Part 77 also identifies the height at which an object may be
considered an obstruction at a designated distance:
§77.17‐ Obstruction standards.
(b) Except for traverse ways on or near an airport with an
operative ground traffic control service furnished by an airport
traffic control tower or by the airport management and
coordinated with the air traffic control service, the standards of
paragraph (a) of this section apply to traverse ways used or to be
used for the passage of mobile objects only after the heights of
these traverse ways are increased by:
(a) An existing object, including a mobile object, is, and a future
object would be an obstruction to air navigation if it is of greater
height than any of the following heights or surfaces:
(1) A height of 499 feet above ground level at the site of the
object.
(2) A height that is 200 feet above ground level or above the
established airport elevation, whichever is higher, within three
nautical miles of the established reference point of an airport,
excluding heliports, with its longest runway more than 3,200 feet
in actual length, and that height increases in the proportion of
100 feet for each additional nautical mile from the airport up to a
maximum of 499 feet.
(1) 17 feet for an Interstate Highway that is part of the National
System of Military and Interstate Highways where overcrossings
are designed for a minimum of 17 feet vertical distance.
(2) 15 feet for any other public roadway.
(3) 10 feet or the height of the highest mobile object that would
normally traverse the road, whichever is greater, for a private
road.
(3) A height within a terminal obstacle clearance area, including
an initial approach segment, a departure area, and a circling
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